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What You Need to Know About Dog Fine Needle Aspiration

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

A vet may recommend fine needle aspiration for a suspicious lump on your dog.

A vet may recommend fine needle aspiration for a suspicious lump on your dog.

What's a Dog Fine Needle Aspiration?

So you found a suspicious lump on your dog, and now your vet is saying he will need a dog fine needle aspiration (FNA). You may be wondering what a fine needle aspiration is and what exactly it entails. My female Rottweiler had one done just last year because of a small lump in her paw.

If your dog has a lump that needs to be checked out, it's always good to be prepared in advance so you know what questions to ask your vet and so you can make the most appropriate decisions which are often needed to be made on the spot. In most cases, a fine needle aspiration is a very important procedure that will help your vet determine if that lump is something to worry about or not.

The truth is, in most cases, your vet cannot tell from visual inspection alone if a lump, bump, or mole is benign or malignant. It's always best to play it safe and rule out cancerous growths, especially since there are certain forms of cancer that are known for being great imitators, meaning that they look like innocent and benign growths when they are not.

Step-by-Step Explanation of the Fine Needle Aspiration Process

So what's a fine needle aspiration, and what does it entail? Also known as fine needle biopsy, a fine needle aspiration is a procedure that requires the insertion of a sterile, hollow, small-gauge needle (fine needle) into the suspicious mass.

  1. The dog's hair may be clipped prior to the procedure and the skin area will be disinfected.
  2. Once the needle is inserted, the plunger of the syringe is drawn back, and cells or fluids are collected (aspirated) in the attached empty syringe. Several areas of the mass may be aspirated.
  3. The collected cells or fluids are then placed on a glass slide and stained so they can be evaluated by the veterinarian by using a microscope (cytology is the term used when studying cells) or they can be sent to pathology for evaluation. When done in-house (in the vet's office), test results may be attained within hours. When sent out to a lab, it may take anywhere between three and five days.

While in most cases, lumps and bumps are evaluated through fine needle aspiration, this procedure may also be utilized to collect cells from internal organs like the liver, lung, kidneys, or lymph nodes. In some cases, fluids may also be collected. For instance, a fine needle aspirate of the bladder may collect urine (a procedure known as cystocentesis), or synovial fluid may be collected from the joints. Even fluid may be collected from the chest or abdomen in the case of dog ascites.

What Does a Fine Needle Aspiration Reveal?

The fluid collected may reveal the type of cells, fungi, or even parasites present in the mass or abnormal organ. Often, fine needle aspirates are successful in correctly diagnosing the following benign or malignant tumors:

  • lymphosarcoma/lymphoma
  • mast cell tumors
  • histiocytomas
  • lipomas
  • sebaceous cysts

Pain and Anesthesia

In most cases of fine needle aspiration of a lump, the pain is minimal and consists of only the sensation of the needle piercing the skin. Sedation or anesthesia is generally not required. However, fractious pets may benefit from a light sedative if they tend to move too much and are uncooperative.

In some cases, things can be a bit more complicated. For instance, in the case of internal organs, the fine needle aspirate is done during an ultrasound, or in the case of lumps in the mouth, heavy sedation or anesthesia may be needed for a fine needle aspiration, which is why many vets prefer to directly perform a surgical biopsy.

Dog Fine Needle Aspiration Cost

As seen, a fine needle aspiration is a minimally invasive procedure that plays an important role in dog diagnostics. Best of all, it's fast and well-tolerated by most animals. If you are in a financially unstable situation, you may be wondering about the costs of fine needle aspiration. The procedure per se is rather inexpensive, but costs can quickly add up if you consider the office visit along with the associated cytology fees.

Generally, office visits for dogs range between $45 and $75. The fine needle aspiration can range between $20 and $40; some include the cytology costs associated with sending it out to the lab, some do not. Usually, the total office visit should not amount to more than $100 to $150.

Of course, costs may vary between one place and another. And if other tests need to be done, the amount will increase. Therefore, expect costs to add up if several needle aspirates need to be taken, if the stained slides are sent to an outside pathology laboratory, rather than in-house, and if your dog requires sedation.

Fine Needle Aspirations Are Highly Accurate, So It's Worth the Price

The money spent for an FNA is for priceless peace of mind since a fine needle aspirate is helpful in ruling out cancerous conditions. According to Pet Cancer Center, a fine needle aspiration was 97.9 percent accurate in diagnosing cancer as compared to a surgical biopsy.

In the case that the cytology results do not match up with what a veterinarian suspects as a malignancy (sometimes, fine needle aspirates come up inconclusive), a surgical biopsy should be done to be sure. Overall, the long-term savings can be substantial when performing a fine needle aspiration if a lump is removed in the early stages of cancer versus when it has been allowed to spread, or worse, metastasize, requiring a more aggressive approach. Not to mention the tranquility that derives when the suspicious lump turns out to be nothing to worry about.

For Further Reading

  • Dog Sebaceous Cysts Home Remedies
    Can your dog's sebaceous cyst be treated naturally with home remedies? Learn when it's best to try home remedies and why surgery is often the best option.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.


AP on May 14, 2015:

embarrassed to admit it -- I allowed a Guelph Veterinarian to remove 2 cysts -- one was fatty tissue the other was not diagnosed -- for $1500.

She did not suggest fine needle aspiration !

Adrienne Farricelli (author) on June 09, 2014:

Thank you DDE, I am happy to hear you enjoyed reading it.

Devika Primić from Dubrovnik, Croatia on June 09, 2014:

I tweeted and facebook shared this useful and interesting hub.